The Kretschmar Hall Observatory
October 28, 2023: Parents' Weekend
For parents' weekend, we opened the observatory on Saturday night for over two hours while approximately 100 students, parents, faculty, and staff came to enjoy the sights. The weather was cool but the moon was full and the skies were cloudless. We used the 16" telescope to look (mostly) at the moon and Jupiter. The 4.5" digital telescope was used to look at fainter objects such as the Lagoon Nebula shown below at left and the Hourglass Nebula shown below at right. The picture of the the Lagoon Nebula was averaged for 8 minutes and the Hourglass Nebula was averaged for 5 minutes.
October 2023: Supernova 2023ixf Update
Back in May, we posted pictures taken with our telescopes from Supernova 2023ixf. Since then more data has been collected showing the brightness as a function of time. The first panel was taken about one week before the star exploded. The other panels show the supernova has been very bright until September. Since then it is starting to burn out.
July 2023: Long Exposure Comparison
On a clear night in July, the Eagle Nebula (M16) was imaged using the 4.5" telescope. The image on the left is what we see in live view mode. The image on the right has been exposed for 33 minutes. The "Pillars of Creation" are right in the center of the picture.
June 2023: Long Exposures
Summer viewing in the Walla Walla valley is always at the mercy of forest fires and dust storms but we have had a few clear nights. While it doesn't work well with large groups, the 4.5" telescope can average images over a long period of time. In the picture below, the Western Veil Nebula was imaged for 36 minutes. A streak of a Starlink satellite can be seen on the right portion of the image.
May 2023: Supernova 2023ixf
On the evening of May 24, we opened the observatory to all of campus. Our viewing line up included the moon, Venus, M13, and the newest supernova on the block (2023ixf). This supernova was discovered on May 19 in the Pinwheel Galaxy M101. Our new 4.5" telescope was used to take the pictures of M101 before and after the supernova explosion.
Our telescope uses universal time so the time stamps are ahead one day from the observation time for pictures taken before midnight. We didn't get the best focus on the telescope but the supernova is so bright it doesn't matter. This image was averaged for seven minutes to minimize vibrations on the roof from all of us standing on it.
May 2023: New Digital Telescope
The 16" Meade telescope has a camera that can connect to it. However, most visitors to the observatory want to look through the telescope rather than watch a monitor so we leave the camera off. This means in our high-light location, we don't get the advantage of image stacking so nebula and galaxies are very dim.
The solution has been to buy a 4.5" digital telescope - the eVscope 2 from Unistellar. This scope has the camera and processing built into it which makes it very easy to use. The image is sent to a viewport on the side of the scope and wirelessly to a tablet. In the picture at the right, the 16" is on the left and the 4.5" is on the right. For normal operation, the 4.5" is placed outside on the roof.
Our first viewing with it was on May 11, 2023. We still need to collimate the scope and identify the spot on the roof with the lowest vibration. The image below to the left is the Whirlpool Galaxy (M51) and the image below to the right is Globular Cluster in the constellation Hercules (M13).
Spring 2023: Events
Through the winter and into the spring, the skies have been mostly cloudy and rainy. Before the dryer weather arrived in late April, the success of the viewing was limited.
- March 2, March U-Days visitors. The moon was visible for about an hour before the clouds got too thick.
- April 3, April U-Days visitors. This event had to be canceled due to rain. Better luck next year.
- April 25, Conceptual, General, and Principles of Physics classes. Excellent views of Venus and the moon.
- April 29, Alumni Weekend participants. This was the best weather we have had all spring with excellent views of the moon, Venus, Mars, and M13. The event ran for two hours and had approximately 100 people attend.
- May 12, Physics and Biophysics majors. Excellent weather but the sunset is getting quite late so the observations also start late.
The moon as imaged by the 16" Meade with a 31mm eyepiece and recorded by a cell phone camera. Image taken by Debbie Muthersbaugh on April 25, 2023.
The exterior view of the observatory with the dome open from the outside observation deck. This image taken by Debbie Muthersbaugh on April 25, 2023.
Fall 2022: Events
With the vibration damping improvement from the tuned mass damper and the clear skies provided by a late summer drought, this has been our best quarter for viewing ever. Jupiter was at its closest approach in decades and Saturn was also in a prime viewing location. We got in the following groups before the fall rains started and put an end to the clear weather:
September 15, Faculty and staff. M13, Jupiter, and Saturn.
October 1, Students in Conceptual Physics, General Physics, and Principles of Physics. Jupiter, Saturn, M13, M31, and the moon.
October 12, All of WWU as announced in the 11am daily email. Again Jupiter, Saturn, M13, M31, and the moon.
October 22, Parents Weekend. Jupiter, Saturn, and M13. The clouds came up during the viewing so the season is over now.
Summer 2022: Vibration Damping
The air legs beneath the telescope reduce the vibration by about 50% but also introduce a drift that is telescope angle dependent. As a result, moving the telescope to a new location always includes steps of fine position correction. This makes the telescope harder to use with large groups of people who want to look at different objects.
The position of a distant object is shown in the graph at left. The blue line shows the undamped position jiggling about in both axes. The yellow line shows the air legs reducing the jiggle but introducing a vertical drift that is almost double the jiggle.
The work this summer focused on trying to get another method of vibration suppression that was as good as the air legs. At the end of the summer, the air legs were removed from the system and a tuned mass damper (TMD) was added. As shown in the picture, the TMD is mounted near the top of the pier and is made of 6 lead bricks floating on sorbothane. The major vibration peaks at 6 and 10 Hz have a reduction of about 5 dB in each axis.
Spring 2022: Vibration Damping and Events
Over Christmas break, a better damping solution than inner tubes was put into place. A vibration damping company, TMC, makes air legs so four of those were put between the telescope and the pier as shown in the picture at right. They reduce down the vibration quite a bit.
May 2022: Observation with the Physics Majors, the General Physics class, Principles of Physics class, and Conceptual Physics class. All the planets rose about 2am so we looked instead at M31 and the moon.
Fall 2021: Vibrational Testing and Events
Over the summer and into the fall, the vibration on the telescope pier was studied using a combination of accelerometers and the camera. The data shown in the picture at left was taken on the eyepiece of the telescope. While there are vibration at higher frequencies, the double peaks at 6 and 9 Hz appear to be the largest ones.
November 2021: Observation was done with the General Physics class and the physics majors in spite of the vibration on the telescope. We had good viewing of the moon, Jupiter, and Saturn.
The first step on vibration suppression was to float the telescope on inner tubes. A special vibration material called sorbothane was also tried. These methods helped a bit but were not enough to be the final solution.
Spring 2021: Events
April 2021: We celebrated the return to campus after the COVID lockdown with an observation evening for the General Physics class and all physics majors. The 16" telescope was used primarily to view the full moon. The portable telescopes on the observation deck were used to view Mars. A number of students used cell phones to capture pictures through the telescopes.
After the viewing in April, a new telescope camera was purchased. The previous camera was about 20 years old, connected to a computer using a parallel part, and was water-cooled. This new camera is USB 3.0 and is air cooled so it is much easier to use. The magnification on the camera is designed for planetary distances. The images on the banner at the top of this page were taken with the new camera.
Before the camera was purchased, vibration was visible in the images seen on the telescope but was difficult to measure. With the camera, the vibration was quantified and a project improvement plan was started.
Observatory History
An observatory was planned for the top of the third floor when Kretschmar Hall was built in 1962. However, since the third floor was not built at that time, neither was the observatory. When a third floor was finally added, it provided an opportunity to complete add this feature.
Click here to watch a video from April 1998 as the dome is being bolted into place. The observatory was completed and opened for use the following year.
The observatory is situated on the roof of Kretschmar Hall and is accessible via stair from the third floor of Kretschmar Hall and via elevator from Chan Shun Pavilion. It is currently equipped with a 16" Schmidt-Cassegrain telescope and an external observation deck for use by smaller telescopes.
The observatory dome from the west.
Another view of the telescope.
The 16" Schmidt-Cassegrain telescope.
A view from the outside looking into the open dome.
